1. Field of the Invention
The present invention relates to a ceramic composition of matter for an apparatus and method of processing (e.g., etching, chemical or physical vapor deposition, etc.) a substrate in a chamber containing a plasma of a processing gas.
2. Description of the Prior Art
The semiconductor industry relies on high throughput, single substrate processing reactors which can be used for a variety of different processes such as thermal chemical vapor depositions (CVD), plasma-enhanced CVD (PECVD), plasma-assisted etching, and deposition topography modification by sputtering. Some processing reactors include processing reactor chambers having a dielectric member (i.e., a dielectric window) wherethrough processing power passes to aid in sustaining a plasma from a processing gas within the reactor chamber for processing a wafer substrate.
Process kits are sometimes employed within the reactor chamber as an aid to processing a wafer substrate. Process kits typically include a capture ring which is supported by a pedestal assembly for retaining a wafer substrate in a generally stationary position for processing. Process kits also typically include a focus ring which in operation is supported by the capture ring for assisting in confining plasma processing gas over the wafer substrate to optimize the processing of the same.
Dielectric members (e.g., dielectric windows) and process kits are generally constructed of a ceramic material, such as high parity alumina ceramics containing 99.5% by weight or higher aluminum oxide (Al2O3). When high density halogen-containing plasmas contact alumina dielectric members and alumina process kits during etching of wafer substrates, erosion of alumina occurs, causing the formation of large particles and contaminant compounds which can damage patterned wafer substrates.
Therefore, what is needed and what has been invented is an improved ceramic composition of matter from which dielectric members and process kits may be constructed. What is further needed and what has been further invented are dielectric members (i.e., dielectric windows) and process kits which are all highly resistant to erosion during etching of a wafer substrate in a high density plasma of an etchant gas.
The present invention accomplishes its desired objects by broadly providing a plasma reactor (e.g. an inductively coupled RF plasma reactor) for processing (e.g., etching, chemical or physical vapor deposition, etc.) substrates. The plasma reactor includes a reactor chamber having a chamber wall and a dielectric member (i.e., a dielectric window) supported by the chamber wall. The dielectric member includes a ceramic composition comprising a ceramic compound and an oxide of a Group IIIB metal from the periodic table by Mendeleef. A pedestal assembly is disposed in the reactor chamber for supporting substrates in the reactor chamber. A processing gas-introducing assembly is engaged to the reactor chamber for introducing a processing gas into the reactor chamber. The plasma reactor further includes a processing power-transmitting member disposed in proximity to the reactor chamber and connected to a processing power source for transmitting power into the reactor chamber to aid in sustaining a plasma from a processing gas within the reactor chamber. If the plasma reactor is an inductively coupled RF plasma reactor, the pedestal assembly is coupled to a bias RF source and the processing power-transmitting member is a coil inductor which is connected to an inductively coupled RF power source.
A process kit may be positioned in the reactor chamber for assisting in the processing of the substrates. The process kit is supported by the pedestal assembly, and includes a capture ring member and a focus ring member, both of which include a ceramic composition comprising a ceramic compound and an oxide of a Group IIIB metal.
The ceramic compound for the ceramic composition of the present invention is preferably selected from the group consisting of silicon carbide, silicon nitride, boron carbide, boron nitride, aluminum nitride, aluminum oxide, and mixtures thereof. More preferably, the ceramic compound is aluminum oxide, especially since it is relatively inexpensive and readily available. The aluminum oxide should be sufficiently pure that it does not xe2x80x9cout-gasxe2x80x9d or include contaminants that could be sputtered onto a substrate during process operation, and it should be chemically stable when exposed to the particular etching processes contemplated. Other materials which may be used to form the ceramic compound include by way of illustration, but are not limited to, the oxide and fluoride forms of aluminum, magnesium and tantalum. The aluminum oxide or other metal-oxide ceramic can be a single crystal oxide, polycrystalline oxide, or amorphous oxide.
The Group IIIB metal for forming a Group IIIB metal oxides of the present invention is preferably a metal selected from the group consisting of scandium, yttrium, the cerium subgroup, and the yttrium subgroup. More preferably, the Group IIIB metal is yttrium; therefore, the oxide of a Group IIIB metal is preferably yttrium oxide.
The ceramic compound and the oxide of a Group IIIB metal may combine in any suitable proportion, preferably such that the ceramic composition comprises from about 30% by weight to about 95% by weight of the ceramic compound and from about 5% by weight to about 70% by weight of an oxide of a Group IIIB metal. More preferably, the ceramic composition comprises a major proportion of the ceramic compound and a minor proportion of the oxide of a Group IIIB metal. Alternatively, the ceramic composition comprises from about 30% by weight to about 95% by weight of the ceramic compound and from about 5% by weight to about 70% by weight of an oxide of a Group IIIB metal, and a minor proportion of a binder agent or a minor proportion of a binder agent and/or an additive agent. The preferred process for forming or producing the dielectric member (i.e., the dielectric window) and the process kit from the ceramic composition is by thermal processing a powdered raw mixture comprising the ceramic compound, the oxide of a Group IIIB metal, a suitable additive agent, and a suitable binder agent.
The present invention also accomplishes its desired objects by broadly providing a method for processing at least one substrate in a chamber containing a plasma processing gas comprising the steps of:
(a) providing a chamber having a chamber wall and containing at least one substrate and a plasma processing gas for processing at least one substrate, and including a dielectric member engaged to the chamber wall and comprising a ceramic composition including a ceramic compound (e.g., Al2O3) and an oxide of a Group IIIB metal (e.g. Y2O3); and
(b) introducing processing power through the dielectric member and into the chamber of step (a) to process the at least one substrate in the plasma processing gas.
The present invention further also accomplishes its desired objects by further broadly providing a method of etching a metal layer on a substrate comprising the steps of:
(a) providing a substrate supporting a metal layer;
(b) disposing the substrate in a chamber including a chamber wall, and a dielectric member supported by the chamber wall and comprising a ceramic composition including a ceramic compound, such as alumina, and an oxide of a Group IIB metal, such as yttrium oxide;
(c) introducing a processing gas into the chamber of step (b); and
(d) introducing processing power through the dielectric member and into the chamber of step (b) to etch the metal layer on the substrate in a high density plasma of a processing gas.
It is therefore an object of the present invention to provide a plasma reactor for processing substrates.
It is another object of the present invention to provide a method for processing a substrate in a chamber containing a plasma processing gas.
It is yet another object of the present invention to provide a ceramic composition which is preferably employed for manufacturing or forming a dielectric window and a process kit.
These, together with the various ancillary objects and features which will become apparent to those skilled in the art as the following description proceeds, are attained by these novel apparatuses and methods, a preferred embodiment thereof shown with reference to the accompanying drawings, by way of example only, wherein: